. >> brown: and we look at how technology allowed police and thpu t >> suarez: plus, we get the perspective of mark shields and david brooks on terror's return to u.s. soil and the rest of the week's news. nighrown: that's all ahead on s "newshour." >> major funding for the pbs newshour has been provided by: >> support also comes from carnegie corporation of new york, a foundation created to do what andrew carnegie called "real and permanent good." celebrating 100 years of philanthropy at carnegie.org. >> and with the ongoing support of these institutions and foundations. and... and friends of the newshour. >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. >> brown: it's been an extraordinary scene and it continues, as boston spent the day locked down by a manhunt for the second brother authorities believe was involved in this week's marathon bombing. that's come after a violent confrontation overnight that left the other bombing suspect and a police officer dead. kwame holman begins our m